Directive radiator



March 7, 1944. BUCHHQLZ 2.3435531 DIRECTIVE RADIATOR Filed April 8 19412 Sheets-Sheet 2 INVENTOR HERBERT BUCf/HOZZ ATTORNEY Patented Mar. 7,1944 DIRECTIVE RADIATOR Herbert Buchholz, Berlin, Germany, assignor toGeneral Electric Company, a corporation of J New York Application April8, 1941, Serial No. 387,512

In Germany January 1, 1940 '7 Claims.

The problem on which the present invention is based consists inproviding a directional wireless transmitter arrangement, in which theacuteness of the angles within which the electromagnetic radiationoccurs is changeable, and in which with simple means the characteristicof the radiation diagram can be influenced. For instance,

by a simple manipulation, the radiation diagram may be made either assteep as possible in upward direction or bearing as flat as possibleagainst the ground or bunched in radiation angles between these twoforms.

With this object in View an arrangement for transmitting shortelectromagnetic oscillations is proposed according to the inventioncomprising a funnel antenna connected with a dielectric space, which islimited by perfect conductors, this funnel antenna being characterizedin that the flank-steepness or the included angle between the walls ofthe funnel antenna may be altered according to the degree ofconcentration desired.

It has been known for a considerable time, that electromagnetic wavescan be propagated by tubes. The arrangement used for such propagationconsists of a metal tube of desired length and of a few centimeters indiameter, the interior of which tube is uniformly filled by a dielectricsuch as air, water and the like. In the hollow space enclosed withinmetallic walls, electromagnetic resonance conditions may be established.

The resonance wave length or frequency is determincd by the dimensionsof the hollow space. Such tubular conductors are often called dielectricconductors or hollow-space conductors. The most favorable attenuationvalues are attained and the dimensions being of the order of the wavelength, the employment of such hollow spaces as resonators is especiallysuitable for ultra-short waves.

In the accompanying drawings Figures 1 and 2 are radiation diagrams forexplaining the principles of the present invention, while Figure 3illustrates a form of receiver for short waves as used in practicing thepresent invention, while Figure 4 is an embodiment of the invention andFigures 5 and 6, modifications thereof.

In dielectric conductors two main oscillation forms are distinguished,namely the electric and the magnetic wave type.

0n the basis of calculations which will not here be gone into but theresults of which are diagrammatically illustrated in Figures 1 and 2,respectively, for the electric and magnetic wave types it has been foundthata hollow-space conductor, perpendicularly inserted in the ground,its open end being flush with the surface of the ground, has a radiationdiagram in which the maximum is situated on the surface of a cone withits point on the axis of the hollow-space conductor. -The opening angle0 of this cone is dependent on the ratio of the operating wave length tothe diameter 'a" of the hollow-space conductor R which is used. Byalteration of these two values the radiation diagram may be made assteep as possible in upwarddirection or bearing on the ground as flatlyas possible.

Funnel-shaped structures may be connected to the open ends of ahollow-space conductor arrangement of the above described type. Atransmitter of very shortwave length is disposed within the interior ofthe hollow-space conductor. The hollow-space conductor with a funnelextending from the same serves for emitting a bunched radiation' Areceiver arrangement as shown in Fig. 3 within a metal funnel T maybeused as antenna for tube waves. The receiver consists of a tube R, onwhich the'metal funnel T is placed. The detector D may be shifted alonga slit in the tube together with theconcentric tuning system placed onthe same. A bridge B serves for tuning the receiver. This arrangementwill sustain horizontally and" vertically polarized oscillations.

The present invention includes the following considerations: Placing afunnel on a hollowspace conductor brings chiefly the advantage, of

increasing the value of a in the radiation crosssection and thereby, ascan be seen from the Figures 1 and 2, causing the direction of themaximal energy radiation to become steeper, without the necessity of, atthe same time, increasing the diameter of the dielectric conductor. Iftherefore the funnel antenna is constructed according to the inventionwhereby its flank-steepness may be regulated while in operation, it ispossible to adjust as desired the direction of the maximal energyradiation. I I

In the form of constructionshown in 'Fig. 4 the flank-steepness of thefunnel connected with tube R is varied as desired by putting onto themain outer funnel of the hollow-space conductor R in the ground Econical additional funnels T1, T2, T3, T4 and so on having'differentopening angles. The funnel T while shown flush with the surface ofground E may alternatively project from the ground or if desired it mayeven be fully outside the ground. The funnel'T or the additional funnelsT1 to T4 are preferably of conical or pyramidshape.

Another form of construction is that shown in Fig. 5, in which theadditional funnels T1 to T4 of Figure 4 may be placed .on a hollow-spaceconductor R which is constructed like a trombone.

struction and prejudicial reflections within conductor Rit, isadvantageous for the radius of curvature of the hollow space'conductor Rto be at least 4 to 5 times as great as the diameter of the tube.Instead of a cylindrical tube the present invention may employ a tubewith rectangular cross-section it is thereby possible to produce apolarized wave in a very simple manner. In this instance the radiationdiagram is much Wider in.

one direction than in the other direction.

Another form of construction for the alteration of the flank angle isshown in Fig.6. With the aid of the device shown in Fig. 6 it ispossible, to continually regulate the direction of the-,rnaximal energyradiation. A single conical, parabolic or pyramid-shaped funnel T isthen used, which is subdivided into several, for instance four sectorsS1 to .84. nected with the shafts 101 to 104, which may besimultaneously operated by means of intermedi ate shafts and gear meansfrom a hand wheel It. By the rotation of hand wheel h, the amountofwhich may be read on a scale disc s, the funnel sectors S; to S4 may befolded together more or less and in this manner the opening angle can becontinuously altered. The different sectors of the metal funnel arepreferably connected together by elastic metallic plaitings such asstrands or the like for filling the gaps between the intermediate spacesas indicated at one point at L. The width of the sectors of the funnelmust preferably .be adapted to cover an adjusting range from 10 to 4.0"for the opening angle.

They may be so arranged that the gaps between the sectors are closed ata middle flank angle and overlap at smallerangles. If desired thesectors may be so arranged as to join one with the other without gaps atgreater angles of adjustment.

The scale disc s may be calibrated, if required, so that the directionof the maximal energy current can be directly read. By means of asuitable transmission between the hand wheel for the flank adjusting andthe oscillatable sectors, the direction of the bunches of rays-may beregulated extremely accurately. In the arrangement shown in Fig. 6, thefunnel T is to be considered as being viewed from the rear side. Thehollowspace conductor R has to be considered as arranged perpendicularlyto the plane of the drawings. The upper bordering edge of the tube Rcoincides approximately with the inner funnel edge.

Instead of a conical or parabolic funnel evidently a pyramid-shapedfunnel may be used also utilizing the form ,of construction shown inFig. 6, but having instead a rectangular crosssection. In the latterinstance it is possible to simultaneously adjust the flank-steepness ofall of the side faces of the funnel with the use of the means as shownin Fig. .6 or, if desired, each flank or pair of opposite flanks may beseparately ad- ;iiusted. Thus if the sides are of difierent width theflank steepness of the narrow side may be adjusted independently of theflank steepness of the wide side.

The funnels used according to the invention may be -fully-metal=lic ormade from wire plaitings. The present invention. is specially suitedfora direction radiator or for navigation; It may also'be used forassisting the blind-landing of airplanes. If required, the presentinvention may be arranged-to radiate or receive horizontally andvertically polarized waves. The invention may be further employed astransmitter as well asa receiver of electromagnetic oscillation.

I claim:

1. A .funnel arrangement adapted to'be .associated with a dielectricwave guide including a These sectors are rigidly ,con-

and means for varying the angle included between opposing ones of saidsectors whereby the directivity of said arrangement is altered.

2. ,A funnel arrangement adapted to be associated with a dielectric waveguide including a plurality of separate wall sectors arranged with theirsmall ends around the end of said guide, means for varying the angleincluded between opposing ones of said sectors whereby the directi-vityof said arrangement is altered and means for establishing electricalcontinuity between said wall sectors.

.3. A funnel arrangement adapted to be associated with a dielectric waveguide including a plurality of separate wall sectors arranged with theirsmall ends around the end of said. guide, means for varying the angleincluded between opposing ones of said sectors whereby the directivityof said arrangement is altered and means for establishing electricalcontinuity between said wall sectors comprising elastic metal plaitingsconnecting adjacent edges of said sectors.

4. A funnel arrangement adapted to be associated with a dielectric waveguide including a plurality of separate wall sectors arranged with theirsmall ends around the .end. of said guide, said sectors being rotatableabout a transverse axis located in an intermediate positionbetween theirinner and outer ends whereby the angle included between opposing ones ofsaid sectors may be varied.

5. A funnel arrangement adapted tobe associated with a dielectric waveguide including a plurality of separate wall sectors arrangedwith theirsmall ends around the end ofsaid guide, said sectors being rotatableabout a transverse axis located in an intermediate position betweentheir inner and outer ends whereby the angle included between opposing.ones of said sectors may be varied and so arranged that theirlongitudinal edges are substantially in alignment at the midpoint oftheir rotation.

6. A funnel arrangement adapted to be associated with a dielectric waveguide including a plurality of separate wall sectors arranged with theirsmall ends around .the end of said guide, said sectors being rotatableabout a transverse axis located in an intermediate position betweentheir inner and outer ends whereb the angle included between opposingones of said sectors may be varied and so arranged that theirlongitudinal edges are substantially in alignment at the midpoint oftheir rotation and means for establishing electrical continuity betweensaid sectors comprising elastic metal plaitings connecting adjacentedgesof said sectors.

7. A funnel arrangement adapted to be associated with a dielectric waveguide including a plurality of separate wall sectors arranged with theirsmall ends around the end of said guide, said sectors being rotatableabout a transverse axis located in an intermediate position betweentheir inner and outer ends whereby the angle included between opposingones of said sectors may be Varied and so arranged that theirlongitudinal edges are substantially in alignment at the midpoint oftheir rotation, means for establishing electrical continuity betweensaid sectors comprising elastic metal plaitings connecting adjacentedges Qf said sectors and gear means coupling said sectors togethejrforsimultaneous rotation.

HERBERT BUCHHOLZ.

